Water storing block and connecting member for water storing block and rain water storing/infiltrating structure

ABSTRACT

A rain-water storing permeation structure can be applied to facilities, such as architectures like buildings, roads, water channels, parks and play grounds, factory sites and domestic sites, as well as water storing blocks used for such a structure and a connecting member for connecting the water storing blocks to each other. The rain-water storing permeation structure of the present invention is provided with a water-shielding layer placed in a recessed section in the ground, a water-storing layer that is constituted by water-storing blocks made of a hard resin foam member having an inner space, and that is placed inside the water-shielding layer, and a lid layer.

The present application is the U.S. national phase under 35 U.S.C. §371of International Application No. PCT/JP00/02359 filed Apr. 12, 2000.

FIELD OF THE INVENTION

The present invention relates to a rain-water storing permeationstructure, and a water storing block and a water-storing blockconnecting member that are used for such a structure, and morespecifically concerns a rain-water storing permeation structure whichcan be applied to facilities, such as architectures like buildings,roads, water channels, parks and play grounds, factory sites anddomestic sites, as well as water storing blocks used for such astructure and a connecting member for connecting the water-storingblocks to each other.

BACKGROUND OF THE INVENTION

Conventionally, most of rain water permeated the soil, or formed groundwater. Rain fall was held in the soil as a whole in various states, andexerted the following functions: It served as a water supply sourcerequired for growth of trees and other plants, adjusted the temperatureof the earth surface through evaporation from the surface of the soilwhen it was hot, and also adjusted the amount of water of rivers.

However, in recent years, buildings, paved roads, etc., have increaseddue to rapid land developments and pavements of roads, resulting in lessland where the soil is directly exposed to the surface in roads, playgrounds and factory sites. For this reason, rain water is allowed toflow sewage systems and rivers through drainage channels, withoutpenetrating the soil, thereby causing the following problems:

(1) Reduction and exhaustion in ground water, and the subsequent landsubsidence.

(2) Occurrence of a heat island phenomenon due to inability of heatremoval from the earth surface because of less water evaporation and thesubsequent less heat absorption by vaporization.

(3) Concentration of rain water into sewage systems and rivers at thetime of a heavy rain, and the subsequent occurrence of deluge and flood,or necessity of works for river control systems, and for expansion ofsewage systems, etc. in an attempt to prevent such disasters.

In order to solve these problems, a method has been proposed in which:the ground is excavated to form a hole, a rain-water storing permeationstructure is installed therein, and parks, roads, etc. are formedthereon, or buildings are built thereon. As described below, two typesof such a rain-water storing permeation structure have been known:

(a) A structure based upon a concrete unit engineering method (NikkeiConstruction, published on Mar. 13, 1998) in which a tank made ofreinforced concrete is constructed as water-shielding material layers,and concrete blocks each of which has a void at a ratio of approximately80% and also has each side set as large as 1.2 m are stacked and housedin this tank, and after a lid layer has been placed, a soil layer isfurther formed thereon so as to form a park, etc.

(b) A center-to-center* block engineering method (disclosed in a catalogof Hayashi Bussan K.K.) in which: a tank is formed by using awater-proof sheet as a water-shielding material layer, and in this tank,water-storing layers are formed by stacking and housing cage-shapedhollow blocks made from polypropylene, each of which has a trapezoidalpyramid shape measuring 360 mm×360 mm in upper surface, 270 mm×270 mm inbottom face, and 260 mm in height, with a void at a ratio ofapproximately 95%, and after a lid layer has been formed thereon, a soillayer is further placed thereon.

However, in the case of the concrete unit engineering method, since theweight of the concrete blocks is very high, its base portion needs to beformed by a high-strength material such as reinforced concrete, and along construction period is required. Consequently, the constructioncosts become high as a whole.

Moreover, upon construction of the water-storing layers, a heavy machineis required in assembling the heavy concrete blocks. When such a heavymachine is used, a large working space is required, with the result thatthe land having a limited area cannot be used to an extent of 100%,thereby limiting the rain-water storing capability.

In the case of the center-to-center* block engineering method, thecage-shaped hollow blocks made of polypropylene (PP) do not have asufficient compression strength; therefore, as is also described in thecatalog, PP blocks can not be stacked with a depth of the water-storinglayers exceeding 3 m. This limits the rain water storing capability perconstruction area. Moreover, PP is not sufficiently resistant todegradation due to microorganisms, etc., in the soil.

The objective of the present invention is to provide a rain-waterstoring permeation structure which is easily constructed without theneed for a heavy machine, has a superior load-resistant property, andprovides a sufficient depth and the subsequent great rain-water storingcapacity, as well as water storing blocks used therein and a connectingmember for connecting these water-storing blocks.

DISCLOSURE OF THE INVENTION

In order to achieve the above-mentioned objective, the rain-waterstoring permeation structure of the present invention features aconstruction which is provided with a water-shielding layer placed in arecessed section in the ground, a water-storing layer that isconstituted by water-storing blocks made of a hard resin foam memberhaving an inner space, and that is placed inside the water-shieldinglayer, and a lid layer.

The water-storing block made of a hard resin foam member having an innerspace has a high compression strength and a superior load resistantproperty, and is light weight and easily manufactured at low costs.Therefore, it is possible to provide a deep construction of thewater-storing layers, and since no heavy machine is required, it ispossible to reduce the working space; thus, it becomes possible toprovide a rain-water storing permeation structure having a highrain-water storing capacity per construction area. In particular, itssuperior load resistant property enables the upper surface to be used asroads, and the coverage of such a wide area makes it possible to storeand utilize a large amount of rain water, and consequently to reducedamage from heavy rain fall.

The water-storing layer is formed by the water-storing blocks that arearranged, stacked and placed therein; thus, a number of small voids forstoring rain water are formed. The percentage of void of thewater-storing block is set to not more than 70%, and more preferably, inthe range of 40 to 65%. The percentage less than 40% causes a reductionin the rain-water storing capacity, and the percentage exceeding 70%tends to cause an insufficient compression strength with respect to theload applied from above.

The upper surface of the rain-water storing permeation structure of thepresent invention can be utilized as sites for buildings, roads, playgrounds, parks, gardens, etc. Therefore, with respect to the surfacelayer, layers, such as concrete bases, paved road surfaces, lawns,tartan tracks, soil, etc. are formed. The level of the upper surface ofthe lid layer is determined by taking into consideration the purpose ofuse, peripheral conditions, etc., and in general, it is set to virtuallythe same level as the peripheral soil layer, with the surface layerbeing included.

The water-shielding layer, which has a function to prevent stored rainwater from leaking and flowing away, is made from a material having nowater permeability. In general, a soil layer surrounds the rain-waterstoring permeation structure; however, not limited by this, structuressuch as concrete walls and concrete fences may surround the rain-waterstoring permeation structure.

The lid layer of the rain-water storing permeation structure of thepresent invention is preferably designed so as to include a waterpermeable material layer.

The lid layer has the following functions: prevention of soil fromflowing into the inner voids of the water-storing block housed insidethe water-storing layer; formation of a soil layer as the surface layerfor effectively utilizing land; and prevention of stress from beingconcentrated on the water-storing block that tends to be adverselyeffected by a local load. On the top of the water-storing blocks,concrete floor plates, tiles, steel plates, natural stone plates, etc.,are placed as the lid layer, and a soil layer is placed thereon as thesurface layer, if necessary. A road may be formed as the surface layer.

In the case when the lid layer having no water permeability is placed asdescribed above, a separate water-collecting facility such as awater-collecting ditch needs to be placed so as to introduce rain waterinto the rain-water storing permeation structure.

The application of a water-permeable material to the lid layer makes itpossible to directly introduce rain water over the rain-water storingpermeation structure into the rain-water storing permeation structure;thus, it is possible to greatly reduce water-collecting facilities to beattached to the rain-water storing permeation structure especially whenit covers a wide area. In this arrangement, even in the event of a heavyrain, no soil forming the soil layer on the rain-water storingpermeation structure is carried by water into a rain-water collectingfacility and lost, which is advantageous. Moreover, when the roadsurface is heated, stored rain water is allowed to evaporate through thewater-permeable lid, thereby cooling the road surface. Thus, it ispossible to effectively reduce the heat island phenomenon.

It is preferable to place soil, water-permeable concrete floor plates, asheet or blocks formed by binding particle-shaped or fiber rubber chipshaving a water-permeable property by using a binder, etc. on thewater-permeable lid layer as the surface layer. In the case of a soillayer, it is more preferable to form a layer structure in which a coarsecrushed stone layer, a ballast layer and a surface soil layer stackedfrom below with the higher layer having a finer grain size.

Moreover, the water-storing block of the present invention features astructure which has an external wall having a polygonal column shapewith an inside void capable of storing water, is made of a hard resinfoam member that can be buried in the soil, and also has an externalwall face support section for receiving a pressure imposed on one faceof the external wall having the polygonal column shape, and a diagonalsupport section connecting to the external wall face support section,for dispersing the pressure imposed on the face.

In the above-mentioned structure, even when it is buried deep in thesoil and subjected to a strong soil pressure imposed sideways on thewater-storing block, the external wall face support section, whichreceives the pressure imposed on one surface of the external wall havingthe polygonal column shape, first exerts a strong resistance, and uponreceipt of a greater soil pressure, the diagonal support sectionconnecting to the external wall face support section effectivelydisperses and weakens the soil pressure; thus, the side wall of theblock becomes less susceptible to distortion and the resulting damageand destruction. Therefore, it is not necessary to take it intoconsideration to slant the pit walls so as to make it wider on thesurface side in its cross-section and to assemble the blocks along itsnormal face; thus, it becomes possible to increase the water-storingcapacity. Moreover, since the block is made of a hard resin foam member,it is light and no problem is raised in the strength even when amulti-stage layered structure is provided. It is also possible to easilyconstruct without increasing construction costs. As a result, theadvantages of the hard polystyrene foam blocks are sufficientlymaintained, and it becomes possible to provide blocks capable ofachieving a water-storing capability with a large capacity.

In the water-storing blocks of the present invention, the void of thewater-storing block is preferably constituted by a void separated into aplurality of sections, and it is preferable that the void is surroundedby at least the diagonal support sections.

With this arrangement, more wall sections surrounding the void areformed so that a strong resistance is exerted against the soil pressureimposed from above, and so that the soil pressure, imposed sideways, iseffectively dispersed by the wall sections surrounding the voidsurrounded by the diagonal support sections.

It is preferable to design the external wall of the water-storing blockof the present invention to have an octagonal column shape formed bychamfering four corners of a virtually square column in an up and downdirection, with each of the edge portions of the side having a circulararc shape protruding outward.

With this arrangement, the sides except the chamfered corners are madeto contact each other so that a number of blocks are two-dimensionallyplaced in a stable manner, and since a void is formed between thecorners, the percentage of void is increased and the amount of waterstoring is increased. Moreover, since the end portions of each side areformed into a circular arc shape protruding outward, it is possible toavoid concentration of stress at the end portions of each side, andconsequently to increase the durability.

In the water-storing block of the present invention, it is preferable toform the corners of the inner walls of the void into an circular arcshape.

This arrangement makes it possible to disperse a stress on the cornersat which concentration of stresses tends to occur, and consequently toensure a higher durability.

The hard resin foam member of the water-storing block of the presentinvention is preferably made of styrene foam having an expansion ratioof at least not less than 20 times.

This arrangement makes it possible to achieve light weight and areduction in the material costs, and an easy lamination process isachieved so that even in a pit deeply formed in the ground, amulti-stage laminated layers are formed, thereby making it possible toincrease the water-storing capacity.

Moreover, the water-storing block connecting member of the presentinvention features that a plurality of claws, made of resin, forsticking the water-storing blocks respectively, are formed on theconnecting member main body in a dispersed manner around the axisthereof, and a housing space for another member is formed between theadjacent claws in the circumferential direction around the axis. Here,the size of housing space for another member is set to a size in which apredetermined number of the claws are inserted in a manner aligned inthe circumferential direction around the axis.

This arrangement provides the following functions [a] through [c]:

[a] For example, in an EUP engineering method (underground water-storingengineering method) in which a plurality of empty water-storing blocksare connected so as to form a civil engineering structure capable ofdrawing water, etc. stored inside the respective water-storing blocks,even in the case when the respective water-storing blocks are connectedby the water-storing block connecting members, since the claws and theconnecting member main body are made of resin, they do not cause rust,thereby making it possible to improve the durability.

[b] Moreover, as described above, the housing space for another memberis formed between the adjacent claws in the circumferential direction ofthe axis, and the size of the housing space for another member is set toa size in which a predetermined number of the claws are inserted in amanner aligned in the circumferential direction around the axis.Therefore, when a plurality of water-storing block connecting members(hereinafter, “water-storing block connecting member” is occasionallyreferred to simply as “connecting member”) are packaged, the respectiveconnecting members 2 can be packaged in an overlapped manner in thefollowing sequence, for example, as illustrated in FIGS. 14 to 16 (inFIG. 14, with respect to the connecting members 2, a connecting memberon the uppermost side of the Figure in an up and down direction isreferred to as the first connecting member, followed by the secondconnecting member, the third connecting member, the fourth connectingmember, the fifth connecting member and the sixth connecting member insuccession downward in the Figure).

{circle around (1)} The respective claws 3 of the second connectingmember 2 are placed adjacent to the respective claws 3 of the firstconnecting member 2 in the circumferential direction around the axis,when viewed in the axis direction of the connecting member main body 4of the first connecting member 2; in this manner, the respectiveconnecting member main bodies 4 are superposed on each other.

{circle around (2)} The respective claws 3 of the third connectingmember 2 are placed adjacent to the respective claws 3 of the secondconnecting member 2 in the circumferential direction around the axis,when viewed in the axis direction of the first (and second) connectingmember 2; in this manner, the respective connecting member main bodies 4are superposed on each other.

{circle around (3)} In this manner, one connecting member 2 issuperposed on another connecting member 2 in succession.

{circle around (4)} When a predetermined number of claws 3 of theconnecting member 2 have been inserted between the respective claws 3 ofthe first connecting member 2, when viewed from the axis direction ofthe first connecting member 2, etc., the above-mentioned processes{circle around (1)} through {circle around (3)} are repeated based upon,for example, the connecting member 2 that was superposed lastly.

In other words, the respective claws 3 of the next connecting member 2are placed adjacent to the respective claws 3 of the connecting member 2in the circumferential direction around the axis, when viewed in theaxis direction of the connecting member 2 that was last superposed; inthis manner, the respective connecting member main bodies 4 aresuperposed on each other.

The claws 3 are normally formed with a narrowed top portion when viewedin the radial direction of the connecting member main body 4, and withthis narrowed top shape, the respective claws 3 of the connecting member2 to be superposed are allowed to enter a space between the claw 3 ofthe adjacent connecting member 2 in the superposing direction and theclaw 3 adjacent to this connecting member 2 in the claw width direction;thus, it is possible to avoid an increase in the distance between theconnecting member main bodies 4 of the two connecting members 2 due tointerference between the claws 3 of the connecting members 2 adjacent toeach other in the superposing direction.

{circle around (5)} By repeating the above-mentioned processes {circlearound (1)} to {circle around (4)}, a plurality of connecting members 2are superposed on one another.

[c] By superposing them in the manner as described in [b] above, thedistance between the connecting member main bodies of the adjacentconnecting members in the height direction of the claws is set to beshorter than the height dimension of the claws.

Therefore, it becomes possible to extend the service life of thewater-storing block connecting member, and also to package a pluralityof water-storing block connecting members in a compact manner.

In the present invention, the following arrangement is preferably made:the connecting member main body of the water-storing block connectingmember is formed into an annular shape with the claws being placed onthe peripheral edge of the connecting member main body; a plurality ofassisting claws, made of resin, for sticking the water-storing blocksrespectively, are placed on the inner circumferential edge of theconnecting member main body, in a manner so as to have the samepositional phase as the above-mentioned claws around the axis; the clawwidth of the assisting claw is set in such a manner that, when viewedfrom the axis direction, the assisting claw is positioned between afirst hypothetical radial line extending from the axis to one edge endin the width direction of the claw and a second hypothetical radial lineextending from the axis to the other edge end in the width direction ofthe claw; a housing space for another assisting member is formed betweenthe adjacent assisting claws in the circumferential direction of theaxis; and the size of the housing space for another assisting member isset to a size that allows a predetermined number of the assisting clawsto enter in the circumferential direction of the axis in an alignedstate.

In the above-mentioned arrangement, the claw width and the layout of theassisting claws are set as described above and the housing space foranother assisting member is formed between the adjacent assisting clawsin the circumferential direction of the axis; therefore, in the casewhen the connecting member main bodies of the respective connectingmembers are superposed in the sequence as described in [b], theassisting claws are placed adjacent to each other in the same manner asthe claws so that it becomes possible to avoid problems such asincapability of the superposing process due to interference between theassisting claws.

Moreover, the assisting claws are placed on the inner circumferentialedge of the annular connecting member main body in such a manner that,in the state where a force is applied so as to allow the claws and theassisting claws to stick the water-storing blocks made of resin, it ispossible to prevent the center portion of the connecting member mainbody from deflecting toward the water-storing block, and also to preventthe claws from tilting outward due to this deflection and sticking thewater-storing blocks in this state. Therefore, it becomes possible tofurther increase the connecting force.

Each of the claws and the assisting claws of the water-storing blockconnecting member of the present invention may be formed into adouble-claw type so that, with the respective centers in the lengthdirection of the claws and the assisting claws being located in between,the first claw portion on one side and the second claw portion on theother side are allowed to stick respective water-storing blocks adjacentto each other in the layer stacking direction.

With this arrangement, it is possible to connect a plurality ofwater-storing blocks in an abutting manner by using one connectingmember, and also to connect the adjacent water-storing blocks in thelayer stacking direction.

Therefore, it is possible to reduce the number of the connecting membersper civil engineering structure, and also to reduce costs required forthe construction work.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view that shows a cross-section of a structuralexample of a rain-water storing permeation structure of the presentinvention in a manner so as to explain a constructed state ofwater-storing blocks and water-permeable polystyrene foam boards.

FIG. 2 is a cross-sectional view of the rain-water storing permeationstructure shown in FIG. 1.

FIG. 3 is a partial enlarged cross-sectional view of an upper endportion of the rain-water storing permeation structure shown in FIG. 1.

FIG. 4 is a perspective view that shows a water-storing block connectingmember for securing water-storing blocks together with each other in therain-water storing permeation structure of FIG. 1.

FIG. 5 is a perspective view that shows an example of use of thewater-storing block connecting member used in arranging and laminatingthe water-storing blocks of FIG. 4.

FIG. 6 is a cross-sectional view that shows a case in which therain-water storing permeation structure of FIG. 1 is formed below aroad.

FIG. 7 is a drawing that shows an example of a horizontalcross-sectional structure of the rain-water storing permeation structureformed below a road.

FIG. 8(a) is a plan view that shows a modified example of thewater-storing block, and FIG. 8(b) is a front view thereof.

FIG. 9 is a partial perspective view showing an example in which thewater-storing blocks of FIG. 8 are arranged.

FIG. 10 is a perspective view that shows a modified example of awater-storing block connecting member for securing the water-storingblocks together with each other.

FIG. 11 is a plan view that shows the water-storing block connectingmember of FIG. 10.

FIG. 12 is a front view of the water-storing block connecting member ofFIG. 10.

FIG. 13 is a development elevation that shows a state in which thewater-storing block connecting members of FIG. 10 are stacked forpackaging.

FIG. 14 is a front view that shows another modified example of thewater-storing block connecting member.

FIG. 15 is a plan view that shows another modified example of thewater-storing block connecting member.

FIG. 16 is a front view of the water-storing block connecting member ofFIG. 15.

THE BEST MODE FOR CARRYING OUT THE INVENTION

With respect to the material for the water-storing block layers used inthe present invention, a known hard resin foam member can be usedwithout any particular limitation; and examples thereof include hardpolyurethane foam, foamed polystyrene (polystyrene foam), etc. A methodfor forming these materials into a water-storing block is notparticularly limited; however, a method in which the foaming resinmaterial is loaded into a mold having a void with a predetermined shapeand foamed is most preferably used.

In particular, the application of polystyrene foam is particularlypreferable in that it is inexpensive and less susceptible to hydrolysisand deterioration due to microorganisms in the soil, and in that sincepolystyrene is a thermoplastic resin, it is reusable.

The polystyrene foam is manufactured through a known manufacturingmethod. More specifically, a method is exemplified in which polystyrenebeads are impregnated with low-boiling-point hydrocarbon such as propaneor butane to form a foaming resin material, and a predetermined amountof this foaming resin material is loaded into a mold with a void havinga predetermined shape that is heated to a predetermined temperature sothat the polystyrene is brought into a fluidizing state with a foamingagent evaporated, thereby forming a foamed material.

The density of the polystyrene foam, which is varied depending on themold void and the amount of load of the resin, the amount of impregnatedfoaming agent to the polystyrene resin, etc., is properly adjusteddepending on its purpose. In the water-storing block of the presentinvention, the density of the foamed material is preferably set in therange of 10 to 50 kg/m³, and the density less than 10 kg/m³ fails toprovide a sufficient compression strength for the block, and in the caseof a heavy block exceeding 50 kg/m³, the weight becomes too great,resulting in degradation in the operability.

With respect to the water-permeable material layer of the rain-waterstoring permeation structure, a water-permeable polystyrene foam layeris preferably used, and the permeability is not particularly limited aslong as rain water is allowed to penetrate therein. The water-permeablepolystyrene may be provided as foamed beads bonded or fused with voidsincluded therein, or as foamed polystyrene having a strip shape with adiameter of several mm to several tens mm, bonded or fused into a plateor a block. It is preferable to use a water-permeable sheet incombination with such a water-permeable polystyrene foam layer. Withrespect to the water-permeable sheet, a known sheet may be used, andmore specifically, examples thereof include fiber materials such aspolyester cloth or a composite material of a fiber material and a resinmaterial.

With respect to the material constituting the water-shielding materiallayer in the rain-water storing permeation structure is not particularlylimited, as long as it can maintain stored rain water without leakage orflow away. Examples thereof include resin, metal, concrete, etc., and awater-proof sheet is more preferably used. The water-storing block usedin the rain-water storing permeation structure in the present inventionhas a light weight; therefore, with respect to the water-shielding layerhousing the block, it is not necessary to use a material having a highstrength such as concrete (at least one water-proof sheet issufficient), and it is possible to avoid corners of the water-storingblock from damaging the water-proof sheet. The application of a flexiblewater-proof sheet makes it possible to carry out a construction work inaccordance with the shape of the soil layers in the pit, and also toshorten the construction period, resulting in effects of easyconstruction and low costs.

With respect to the arrangement and material of the water-proof sheet,not particularly limited, any material which is generally used as awater-proof sheet may be used. More specifically, a sheet having athickness of approximately 4 mm, formed by nonwoven fabric of organicfibers impregnated and coated with an asphalt-based material, or a sheethaving a thickness of approximately 0.5 mm to 5 mm, formed by combininga cured composition of a rubber material, such as chloroprene rubber,butyl rubber or ethylene propylene rubber (EPDM), with a woven cloth ora nonwoven fabric of natural fibers and synthetic fibers, if necessary,is preferably used. Besides the rubber material crosslinked throughcuring, a thermoplastic resin or a thermoplastic elastomer, which issolely formed into a sheet or combined with fibers to form a sheet, mayalso be used. In particular, a composite sheet formed by an organicnonwoven fabric and an asphalt-based material has a superior expandingproperty, and is easily affixed to a recessed shape of the pit in theground, and inexpensive; therefore, this material is preferably used.

Referring to Figures, the following description will discuss embodimentsof the present invention. In the following examples, polystyrene foamhaving a density of 25 kg/cm³ is used as the hard resin foam member. Thewater-storing block 5 having a shape shown in FIG. 4 is used as thewater-storing block. With respect to the water-permeable polystyrenefoam material, a water-permeable polystyrene foam board (trade name:Tummy Block, made by Tamai Kankyo System K.K.), which was obtained byforming strip polystyrene foam into a board shape having a thickness of250 mm, was used.

FIG. 1 is a perspective view of a vertical cross-section that shows anarrangement and a laminated state of water-storing blocks andwater-permeable polystyrene foam boards. FIG. 2 shows a cross-sectionalconstruction of the rain-water storing permeation structure of FIG. 1.The rain-water storing permeation structure, exemplified by FIGS. 1 and2, has a bottom surface having a length of 6 m and a width of 6 m, and adepth of 4 m from the ground surface, and the side walls of thewater-storing layer are widened upward with an angle of 45° from thebottom surface; the upper surface has a square shape, each side having12 m. The rain-water storing permeation structure 1 has a trapezoidalreversed pyramid shape, and is constituted by the following layersplaced along the respective pit faces in the ground with the side faceshaving a tilt angle of 45°: a water-shielding sheet layer 3 using acomposite sheet having a thickness of 4 mm made of an organic fibernonwoven fabric and an asphalt-based material (trade name: Custom NT,made by Nisshin Tokushu Kensetsu K.K.) as a water-shielding materiallayer 3; a water-permeable polystyrene foam board layer 9 formed as thelowermost layer; a water-storing layer 6 formed by stackingwater-storing blocks 5 having inner spaces; a layer 11 having two stagesof water-permeable polystyrene foam board layers; and a lid layer 17made of a water-permeable sheet 13.

A pump 18 is installed in the rain-water storing permeation structureshown in FIGS. 1 and 2 so as-to draw rain-water stored therein. In thecase when the rain-water storing permeation structure is formed into amound-shape and placed higher than the peripheral portion like a road,instead of a pump, a water-releasing means such as valve may be used.Moreover, as illustrated in FIGS. 1 and 2, a sand layer 4 is preferablyplaced on the outside of the water-shielding sheet layer 3.

FIG. 3 shows the structure of the upper end portion of the rain-waterstoring permeation structure in an enlarged manner. The rain-waterstoring permeation structure 1 is shielded by the water-shielding sheet3 from the peripheral soil of the pit, and provided with thewater-storing layer 6 formed by the polystyrene foam blocks 20 (FIG. 5)serving as the arranged and stacked water-storing blocks 5, and the lidlayer 17 placed thereon that is formed by the water-permeable sheetlayer 13 and the water-permeable polystyrene foam board layer 11.Moreover, on the lid layer 17, a surface layer 7, constituted by acrushed stone layer 32, a gravel layer 31 and a soil layer 15, isformed. Each of spaces having a triangular shape formed by theperipheral soil faces of the pit and the rectangular water-storingblocks is filled with a water-permeable polystyrene foam board cut intoa proper shape as a filling member 34.

The water-shielding sheet 3 is affixed to the level of the upper end ofthe water-storing layer 6 formed by the water-permeable polystyrene foamboards 11 and the water-storing blocks 5, and secured to the peripheralground portion. The securing of the water-shielding sheet 3 is carriedout as follows: First, the peripheral ground is widely dug up in thevicinity of the securing section, and the water-shielding sheet 3 isplaced. Then, the end portions are fixed by, for example, stakes 41 andanchor pins 43, and the predetermined water-storing blocks 5 and thewater-permeable polystyrene foam boards 11 are arranged thereon, and thewater-permeable sheet 13 is further placed thereon and properly secured.

Upon arranging and stacking the water-storing blocks 5, it is preferableto use connecting members 2, and FIG. 4 shows an example of such aconnecting member. The connecting member 2 has such functions that itprevents the water-storing blocks from moving laterally, and alsoensures the load-resistant strength of the water-storing layer. Theconnecting member 2, shown in FIG. 4, is formed by machining an endportion of a steel plate having a proper size into a saw-teeth shape andbending this in the vertical direction, and this is placed between thefoamed materials of the stacked upper and lower polystyrene foam blockswith the saw-teeth end portion cutting therein; thus, it is allowed toexert a predetermined function. The shape of the connecting member 2 isnot particularly limited as long as it exerts the above-mentionedfunction.

FIG. 5 shows an example in which the polystyrene foam blocks 20, used inFIGS. 1 and 2, are arranged and stacked by using the connecting membersshown in FIG. 4. This polystyrene foam block 20 has a size of 1000 mm inlength, 1000 mm in width and 250 mm in height, and is provided with fourinner spaces 21, each penetrating in an up and down direction and havinga size of 350 mm in length and 350 mm in width. When viewed from above,this has a lattice structure. The foamed material serving as a partition23 of the spaces has a thickness of 150 mm, and the foamed materialforming the peripheral walls 45 has a thickness of 75 mm. When these arearranged and stacked without gaps, the inner spaces are arranged withintervals of 150 mm. The foamed material, which forms the partition 23of the spaces and the peripheral walls 25, is provided with a slit 27having a width of 25 mm and a height of approximately 100 mm so thatrain water is allowed to freely flow between the right and left innerspaces.

The shape of the polystyrene foam blocks is not limited by theabove-mentioned shape; and any shapes, such as a column shape and apolygonal pillar shape, may be used as long as the shape is not brokenby a load imposed from above. Moreover, it is not necessary for all thewater-storing blocks to have the same shape, and blocks having differentshapes may be freely combined. It is not necessary for all thewater-storing blocks used for the water-storing layer to have the innerspaces, and hard resin foam members without spaces may be interpolatedupon arranging and stacking the blocks. Here, with respect to thearranged and stacked water-storing blocks, they are not necessarilyarranged and stacked without gaps between them, as long as theywithstand a load applied from above. Moreover, with respect to thespaces for storing water, in addition to the inner spaces provided inthe blocks themselves of the water-storing blocks, those resulting fromthe arranging and stacking state of the water-storing blocks may beincluded.

The inner space of the polystyrene foam block 20 serving as thewater-storing block 5 of FIG. 5 has a shape that is opened in thevertical direction; however, it may have partitions in the horizontaldirection. In this case, however, since the partitions in the horizontaldirection is less contributive to the strength against a load appliedfrom above, resulting in a reduction in the amount of water storing. Itis preferable that the inner space has a shape that is opened in thevertical direction.

In the construction example shown in FIG. 5, the water-storing block 5is placed with the connecting member 2 sticking the foamed member at thecenter of the partition 23 of the lattice-shaped water-storing blocklocated below, and the connecting member sticks the respective cornersof the peripheral walls 25 of four water-storing blocks 5 located as itsupper layer so as to secure them; thus, the arrangement is made suchthat the center of the water-storing block of the lower layer ispositioned at the connecting point of the four corners of thewater-storing blocks of the upper layer. This arrangement preferablyprevents the occurrence of a partial descent even when a partial load isimposed on the top of the rain-water storing permeation structure.

FIG. 6 shows an example in which a rain-water storing permeation layeris placed beneath a paved road.

The paved road is constructed as follows: A paved road face 51 isplaced, below this layer are placed a soil layer 15 and a concrete floorplate 52 serving as the lid layer 17, below this is placed awater-storing layer 6 formed by arranging the water-storing blocks 5,and below this is placed a water-proof sheet layer 3. Here, in thisexample, in order to receive the load of the concrete floor plate 52uniformly in a dispersed manner, a normal polystyrene foam block layer57 is formed as the lower layer of the concrete floor plate 52. On theroad side, a water-collecting funnel 53 is installed and a water-passagehole 55 is formed in the water-collecting funnel 53 so that rain wateris allowed to permeate the water storing layer 6 through thewater-passage hole 55.

In recent years, a water-permeable paving method has been developed, andin the case of a water-permeable paved road face, it is possible to usea water-permeable lid, exemplified by FIG. 1, may be used, withoutinstalling the water-collecting funnel 53 with the water-passage hole55.

The rain-water storing permeation layer shown in FIG. 6, placed below apaved road, has the same shape as exemplified in FIGS. 1 and 2, and thepaved traffic road has a width of 7000 mm. The rain-water storingpermeation layer may be continuously formed in the length direction ofthe road face, or storing layers having a structure exemplified by FIG.6 may be intermittently formed.

On both sides of the paved traffic road are formed bushes and a sidewalk, and a water-permeable pavement layer 59 is formed. In the samemanner as the example shown in FIG. 2, the soil layer 15, the gravellayer 31 and crushed stone layer 32 are formed from the top, and thewater-permeable sheet layer and the water-permeable polystyrene foamboard layer 11 are placed as a lid layer so that both rain water on thetraffic road and rain water on the side walk are directed to thewater-storing layer 6 and stored.

Here, FIG. 7 shows a structure of the cross-sections in the horizontaldirection taken along A—A and B—B of the rain-water storing permeationstructure of FIG. 6.

The rain water stored in the rain-water storing permeation structure maybe used as fire-extinguishing water, emergency drinking water afterpurification by a water-purifying device, and sprinkler-use water forplants.

ANOTHER PREFERRED MODE

(1) The water-storing block used in the present invention may have anarrangement shown in FIG. 8. FIG. 8(a) shows a plan-view construction ofthe water-storing block, and FIG. 8(b) shows a front-view construction.FIG. 9 shows an example in which the water-storing blocks are partiallystacked two-dimensionally. The water-storing block 65 is made of foamedstyrol, which is one example of the hard resin foam member, and has anoctagonal column shape formed by a virtually square column with fourcorners chamfered in an up and down direction; thus, its outer wall isconstituted by four wider outer wall faces 65 a and slightly narrowercorner faces 65 b connecting these. Each side 65 c at which each outerwall face 65 a and each corner face 65 b intersect each other ispreferably formed into an circular arc shape protruding outward, withouthaving a sharp sticking shape. Thus, it is possible to avoidconcentration of stresses at this portion caused by externally appliedforces. Although not shown in the Figure, in the case when thewater-storing blocks 65 are stacked in a manner as partially shown inFIG. 9, the connecting members, as shown in FIG. 4, are used to securethe water-storing blocks 65 so as not to be easily offset. Here, withrespect to the stacking method of the water-storing blocks 65, in FIG.9, the upper and lower water-storing blocks are stacked withoutoffsetting them; however, they may be stacked in an offset manner in adiagonal direction so as to superpose the void 62 b and the void 62 c ofthe upper and lower water-storing blocks and allow them to communicatewith each other.

Inside the outer wall constituting the water-storing block 65, aplurality of voids 62 are formed in a separate manner so as to storewater. These voids 62 is constituted by a first void 62 a in the centerhaving a comparatively large and virtually square column shape, and foursecond voids 62 b, each of which is formed along each side of the firstvoid 62 a, and located between each side and each corner face 65 b witha narrow width along each side of the first void 62 a and each cornerface 65 b. Here, a wall portion surrounding the first and second voids62 a and 62 b exerts a reinforcing effect against an externally appliedforce imposed on the water-storing block 65. In other words, the wallportion, which extends from the virtually center of the outer wall face65 a inward in a direction virtually orthogonal to the outer wall face65 a and which is sandwiched between the adjacent second voids 62 b,forms an outer wall face supporting portion 63, and a wall portion,which starts from the outer wall face supporting portion 63, and issurrounded by the second void 62 b and the first void 62 a, forms adiagonal supporting portion 64; thus, in the case when an external forceis exerted on the outer wall face 65 a, the external force is supportedby the outer wall face supporting portion 63 so that the outer wall face65 a is not easily distorted. Even if a greater external force isexerted on the outer wall face 65 a, the external force is supported bythe outer wall face supporting portion 63, and the external force isalso divided into two directions effectively by the diagonal supportingportion 64 connecting to the outer wall face supporting portion 63;thus, even in such a case, the outer wall face 65 a is not easilydistorted, and allowed to exert strong resistance.

Therefore, the water-storing vessel constituted by a plurality of suchwater-storing blocks 65 is less susceptible to damage and destruction,and allowed to maintain a great water-storing capability. Additionally,in any of the voids 62 a and 62 b, each of the inner wall cornerportions is formed into a concave circular arc shape so as to avoidforming a sharp edge portion on which stresses tend to concentrate.

Moreover, in the case when a plurality of water-storing blocks 65 aretwo-dimensionally arranged, a void 62 c surrounded by the water-storingblocks 65 themselves is formed inside thereof. In other words, the void62 c, surrounded by the corner faces 65 b of the water-storing blocks65, is formed so that it is possible to increase the percentage of void,and also to increase the amount of water storing.

A passage hole 66 having a semicircular shape in its cross-section,which allows the voids 62 to communicate with each other, is formed ineach of the upper center portion and the bottom portion of each cornerface 65 b and on each wall portion on an extended line therefrom of thewater-storing block 65; thus, it is possible to avoid storing water onlyin specific voids, and consequently to allow the voids 62 to have thesame water level. In the case when the water-storing blocks 65 arestacked, as illustrated in FIG. 9, the passage holes 66, each having avirtually semicircular shape, are formed into a tube shape having avirtually circular shape in its cross-section by the water-storingblocks 65 stacked in an up and down direction. Here, the passage hole 66may be formed into another shape, for example, a slit shape, so thatwhen the water-storing blocks 65 are stacked vertically, the holes 66are formed into a passage hole having an elongated shape, or may beformed into an elliptical shape; however, when they are arranged to forma into a tube shape having virtually circular shape in its cross-sectionas in the case of the present embodiment, it becomes possible toincrease resistance against an external force and consequently toprovide a superior strength, and it is also possible to preferably avoidconcentration of stresses securely on the inner circumferential faces.Moreover, FIGS. 8 and 9 have exemplified a case in which one passagehole is formed in each of the virtually upper center portion and thebottom portion of each corner face 65 b; however, the number andformation position thereof are not particularly limited by this example;and a plurality of holes may be formed, and it may be formed in aposition other than the virtually center position of each corner face 65b.

(2) In order to increase the percentage of void of the water-storingblocks, another arrangement may be proposed in which a notched sectionis formed in each corner portion constituting the outer wall. In thecase when a water-storing layer is formed by aligning side by side orstacking a plurality of water-storing blocks, this arrangement makes itpossible to form a void surrounded by the notched sections formed in therespective corner portions; thus the percentage of void is increased andthe amount of water storing is also increased.

(3) FIGS. 10 to 12 show a modified example of the water-storing blockconnecting member.

An explanation will be given of an example in which the water-storingblock connecting member 12 is applied to an EUP engineering method. TheEUP engineering method refers to an engineering method wherein among aplurality of empty foamed styrol blocks 20, circumferential portions ofthe adjacent foamed styrol blocks 20 in the lateral direction areface-to-face connected through a connecting member 12, and the adjacentfoamed styrol blocks 20 in an up and down direction (in the stackingdirection) are also connected to each other through a connecting member12 so as to form a civil engineering structure; thus, rain water, etc.,is stored inside the foamed styrol blocks 20 so as to be drawn later.

The connecting member 12 is made of high-impact polystyrene, and molded,and four claws 33 that respectively stick a plurality of adjacent foamedstyrol blocks 20 in the lateral direction and in the up and downdirection (in the stacking direction) are placed on the peripheral edgeof a connecting member main body 4 having a virtually disc doughnutshape in a uniformly dispersed manner around the axis of the connectingmember main body 4, and four assisting claws 35 shorter than the claws33 are placed on the inner circumferential edge of the connecting membermain body 4 in a manner so as to have the same positional phase as theclaws 33 around the axis. Here, an another-member housing space S2 isformed between the adjacent claws 33 in the circumferential direction ofthe axis, and assisting another-member housing space S2 is formedbetween the adjacent assisting claws 35 in the circumferential directionof the axis. In FIG. 12, O represents the axis of the connecting membermain body 36.

Each of the claws 33 and the assisting claws 35 is formed into a doubleclaw shape having a T-letter format in its cross-section with narrowedtops so that, with the respective centers in the length direction of theclaw 33 and the assisting claw 35 being located in between, the firstclaw portion on one side and the second claw portion on the other sideare allowed to stick respective foamed styrol blocks 20 adjacent to eachother in the stacking direction (the foamed styrol blocks 20 aresufficiently soft so as to be stuck by the claws 33 and the assistingclaws 35).

The size of the another-member housing space S1 is set to a sizeallowing a predetermined number of the claws 33 to be inserted thereinside by side in the circumferential direction of the axis, and the sizeof the assisting another-member housing space S2 is set to a sizeallowing a predetermined number of the assisting claws 35 to be insertedtherein side by side in the circumferential direction of the axis.

Here, the claw width of the assisting claw 35 is set in such a mannerthat, when viewed from the axis direction, the assisting claw 35 ispositioned between a hypothetical radial line L1 extending from the axisO to one edge end in the width direction of the claw 33 and ahypothetical radial line L2 extending from the axis O to the other edgeend in the width direction of the claw 33.

In the connecting member 12 having the above-mentioned structure, theclaws 33 and the assisting claws 35 are allowed to stick into the foamedstyrol blocks 20 when the worker stamps thereon with the foot or makesother like movements, so that the adjacent foamed styrol blocks 20 areconnected to each other.

Next, an explanation will be given of a means for packaging a number ofthe connecting members 12 having the above-mentioned structure (see FIG.13, in FIG. 13, with respect to the connecting members 12, a connectingmember on the uppermost side of the Figure in an up and down directionis referred to as the first connecting member, followed by the secondconnecting member, the third connecting member, the fourth connectingmember, the fifth connecting member and the sixth connecting member insuccession downward in the Figure).

{circle around (1)} When viewed in the axis direction of the connectingmember main body 36 of the first connecting member 2, the respectiveclaws 33 of the second connecting member 12 are placed adjacent to therespective claws 33 of the first connecting member 12 in thecircumferential direction around the axis, and the respective assistingclaws 35 of the second connecting member 12 are placed adjacent to therespective assisting claws 35 of the first connecting member 12 in thecircumferential direction around the axis; in this manner, therespective connecting member main bodies 36 are superposed on eachother.

{circle around (2)} When viewed in the axis direction of the first (andsecond) connecting member 12, the respective claws 33 of the thirdconnecting member 12 are placed adjacent to the respective claws 33 ofthe second connecting member 12 in the circumferential direction aroundthe axis, and the respective assisting claws 35 of the third connectingmember 12 are placed adjacent to the respective claws 35 of the secondconnecting member 12 in the circumferential direction around the axis;in this manner, the respective connecting member main bodies 36 aresuperposed on each other.

{circle around (3)} As described above, one connecting member 12 issuperposed on another connecting member 12 in succession.

{circle around (4)} If, when viewed from the axis direction of the firstconnecting member 2, etc., a predetermined number of claws 33 of theconnecting member 2 have been inserted between the respective claws 33of the first connecting member 12 and a predetermined number ofassisting claws 35 of the connecting member 12 have been insertedbetween the respective assisting claws 35 of the first connecting member12, the above-mentioned processes {circle around (1)} through {circlearound (3)} are repeated based upon, for example, the connecting member12 that was superposed lastly.

In other words, when viewed in the axis direction of the connectingmember 12 that was last superposed, the respective claws 33 of the nextconnecting member 12 are placed adjacent to the respective claws 33 ofthe connecting member 12 in the circumferential direction around theaxis, and the respective assisting claws 35 of the next connectingmember 12 are placed adjacent to the respective assisting claws 35 ofthe connecting member 12 that was last superimposed in thecircumferential direction around the axis; in this manner, therespective connecting member main bodies 36 are superposed on eachother.

{circle around (5)} A plurality of the connecting members 12 aresuperposed on one after another by repeating the above-mentionedprocesses {circle around (1)} through {circle around (4)}.

(4) FIG. 14 shows still another modified example of the connectingmember. This connecting member is also applied to one-side claw typewherein the claws 33 and the assisting claws 35 are formed on one plateface of the connecting member main body 36.

(5) FIGS. 15 and 16 show a connecting member 22 in still anothermodified example.

Different from the connecting member in the modified example shown inFIG. 12, this connecting member 22 is not provided with assisting claws,and a connecting member main body 46 is formed into a virtually discshape (not an annular shape). Other structures are the same as those ofthe connecting member of the above-mentioned modified example. Withrespect to the packaging means of the connecting member 22, anexplanation can be given based upon FIG. 13 that shows the packagingmeans in the above-mentioned modified example (that is, FIG. 13 showsboth of the packaging means of the connecting member of theabove-mentioned modified example and the packaging means of theconnecting member of another modified example).

The packaging means of this connecting member is the same as thepackaging means explained on the connecting member of theabove-mentioned modified example; therefore, the explanation thereof isomitted.

Moreover, the above-mentioned claws 33 can be applied to one-side clawtype wherein those are formed on one plate face of the connecting membermain body 36.

The connecting member of the one-side claw type is used when, forexample, a plurality of the foamed styrol blocks 20 on the uppermostlayer are face-to-face connected to each other. The material of theconnecting member is not particularly limited to high-impactpolystyrene, and may be, for example, polypropylene, or polycarbonate.

The shape of the connecting member main body 36, 46 is not limited tothe above-mentioned shape.

The number of the claws 33 and the assisting claws 35 is not limited tothe number shown in the above-mentioned modified example. Moreover, thesize of the connecting member main body 36, 46 and the number of theclaws 33 and the assisting claws 35 may be set different from those ofthe above-mentioned modified example so that the size of theanother-member housing space SI and the size of the assisting anothermember housing space S2 may be set different from the sizes of thespaces in the above-mentioned embodiment.

The cross-sectional shape of the claws 33 and the assisting claws 35 isnot limited to the T-letter shape, and may be, for example, a triangularshape.

The connecting member used for connecting the foamed styrol blocks 20 toeach other in an EPS engineering method may be designed to structuresused in the connecting member of the above-mentioned modified exampleand another modified example. The EPS engineering method refers to anengineering method wherein the adjacent foamed material blocks in thelateral direction are face-to-face connected, and the adjacent foamedmaterial blocks in an up and down direction are also connected to eachother so as to form a civil engineering structure; and this method isparticularly effective in solving the problem of weak ground.

(6) With respect to the above-mentioned foamed resin, a foamed resin maybe provided by making a resin impregnated with carbon dioxide gas or thelike in a super critical state so as to be expand, and the resultingfoamed resin, which has a fine, uniform foaming radius with a diameterin the range of 1 to 30 μm and a high strength, may be used. Theapplication of this material is more preferable because it furtherincreases the resistance against the soil pressure, and also increasesthe percentage of void to not less than 70%.

INDUSTRIAL APPLICABILITY

The rain-water storing permeation structure of the present invention isapplicable to facilities, such as architectures like buildings, roads,water channels, parks and play grounds, factory sites as well asdomestic sites.

What is claimed is:
 1. A rain-water storing permeation structurecomprising: a water-shielding layer placed in a recessed section in theground, said recessed section having a bottom and outwardly slanted sidesurfaces; a water-storing layer comprising multiple layers ofwater-storing blocks which are made of a hard resin foam member having aspecific gravity lower than water, wherein multiple water-storing blocksare placed side by side and one upon another using connecting membershaving claws, and an upper layer of said multiple layers comprises morewater-storing blocks than does a lower layer, each block having an innerspace and rigid walls, the water-storing layer being placed inside thewater-shielding layer; a lid layer formed on the water-storing layer,comprising a water-permeable layer made of a water-permeable material;and a surface layer covering said lid layer and being leveledsubstantially with said ground, said surface layer having an area widerthan that of the bottom of the recessed section and maintaining itslevel by resisting the buoyancy of the water-storing layer when storingwater therein.
 2. The rain-water storing permeation structure accordingto claim 1, wherein the water-permeable material is a water-permeablepolystyrene foam member.
 3. The rain-water storing permeation structureaccording to claim 1, wherein the hard resin foam member is apolystyrene foam member.
 4. The rain-water storing permeation structureaccording to claim 3, wherein the polystyrene foam member has a densityin a range of 10 to 50 kg/m³.
 5. The rain-water storing permeationstructure according to claim 1, wherein the water-shielding layer ismade of a water-proof sheet.
 6. The rain-water storing permeationstructure according to claim 1, wherein the surface layer comprises apaved road having a width smaller than that of the water-storing layer.7. The rain-water storing permeation structure according to claim 1,wherein the water-storing layer is disposed substantially parallel tothe ground surface and the bottom surface of the recessed section of theground.
 8. The rain-water storing permeation structure according toclaim 1, wherein the surface layer comprises a crushed stone layer, agravel layer, and a soil layer toward a surface of the surface layer.